/*
 * @(#)AckEquivExample.java	1.6 00/08/18
 * 
 * Copyright (c) 2000 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * Sun grants you ("Licensee") a non-exclusive, royalty free, license to use,
 * modify and redistribute this software in source and binary code form,
 * provided that i) this copyright notice and license appear on all copies of
 * the software; and ii) Licensee does not utilize the software in a manner
 * which is disparaging to Sun.
 *
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY
 * IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR
 * NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE
 * LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING
 * OR DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS
 * LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT,
 * INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER
 * CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF
 * OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES.
 *
 * This software is not designed or intended for use in on-line control of
 * aircraft, air traffic, aircraft navigation or aircraft communications; or in
 * the design, construction, operation or maintenance of any nuclear
 * facility. Licensee represents and warrants that it will not use or
 * redistribute the Software for such purposes.
 */
import javax.jms.*;

/**
 * The AckEquivExample class shows how the following two scenarios both ensure
 * that a message will not be acknowledged until processing of it is complete:
 * <ul>
 * <li> Using an asynchronous receiver (message listener) in an 
 * AUTO_ACKNOWLEDGE session
 * <li> Using a synchronous receiver in a CLIENT_ACKNOWLEDGE session
 * </ul>
 * <p>
 * With a message listener, the automatic acknowledgment happens when the
 * onMessage method returns -- that is, after message processing has finished.
 * <p>
 * With a synchronous receive, the client acknowledges the message after
 * processing is complete.  (If you use AUTO_ACKNOWLEDGE with a synchronous
 * receive, the acknowledgement happens immediately after the receive call; if
 * any subsequent processing steps fail, the message cannot be redelivered.)
 * <p>
 * The program contains a SynchSender class, a SynchReceiver class, an 
 * AsynchSubscriber class with a TextListener class, a MultiplePublisher class,
 * a main method, and a method that runs the other classes' threads.
 * <p>
 * Specify a queue name and a topic name on the command line when you run the 
 * program.  The program also uses a queue named "controlQueue", which should be
 * created before you run the program.
 *
 * @author Kim Haase
 * @version 1.6, 08/18/00
 */
public class AckEquivExample {
    final String  CONTROL_QUEUE = "controlQueue";
    String        queueName = null;
    String        topicName = null;
    int           exitResult = 0;

    /**
     * The SynchSender class creates a session in CLIENT_ACKNOWLEDGE mode and
     * sends a message.
     *
     * @author Kim Haase
     * @version 1.6, 08/18/00
     */
    public class SynchSender extends Thread {
        
        /**
         * Runs the thread.
         */
        public void run() {
            QueueConnectionFactory  queueConnectionFactory = null;
            QueueConnection         queueConnection = null;
            QueueSession            queueSession = null;
            Queue                   queue = null;
            QueueSender             queueSender = null;
            final String            MSG_TEXT = 
                             new String("Here is a client-acknowledge message");
            TextMessage             message = null;

            try {
                queueConnectionFactory = 
                    SampleUtilities.getQueueConnectionFactory();
                queueConnection = 
                    queueConnectionFactory.createQueueConnection();
                queueSession = queueConnection.createQueueSession(false, 
                    Session.CLIENT_ACKNOWLEDGE);
                queue = SampleUtilities.getQueue(queueName, queueSession);
            } catch (Exception e) {
                System.out.println("Connection problem: " + e.toString());
                if (queueConnection != null) {
                    try {
                        queueConnection.close();
                    } catch (JMSException ee) {}
                }
                System.exit(1);
            }

            /*
             * Create client-acknowledge sender.
             * Create and send message.
             */
            try {
                System.out.println("  SENDER: Created client-acknowledge session");
                queueSender = queueSession.createSender(queue);
                message = queueSession.createTextMessage();
                message.setText(MSG_TEXT);
                System.out.println("  SENDER: Sending message: " 
                    + message.getText());
                queueSender.send(message);
            } catch (JMSException e) {
                System.out.println("Exception occurred: " + e.toString());
                exitResult = 1;
            } finally {
                if (queueConnection != null) {
                    try {
                        queueConnection.close();
                    } catch (JMSException e) {
                        exitResult = 1;
                    }
                }
            }
        }
    }
    
    /**
     * The SynchReceiver class creates a session in CLIENT_ACKNOWLEDGE mode and
     * receives the message sent by the SynchSender class.
     *
     * @author Kim Haase
     * @version 1.6, 08/18/00
     */
    public class SynchReceiver extends Thread {

        /**
         * Runs the thread.
         */
    	public void run() {
            QueueConnectionFactory  queueConnectionFactory = null;
            QueueConnection         queueConnection = null;
            QueueSession            queueSession = null;
            Queue                   queue = null;
            QueueReceiver           queueReceiver = null;
            TextMessage             message = null;

            try {
                queueConnectionFactory = 
                    SampleUtilities.getQueueConnectionFactory();
                queueConnection = 
                    queueConnectionFactory.createQueueConnection();
                queueSession = queueConnection.createQueueSession(false, 
                    Session.CLIENT_ACKNOWLEDGE);
                queue = SampleUtilities.getQueue(queueName, queueSession);
            } catch (Exception e) {
                System.out.println("Connection problem: " + e.toString());
                if (queueConnection != null) {
                    try {
                        queueConnection.close();
                    } catch (JMSException ee) {}
                }
                System.exit(1);
            }
   	
            /*
             * Create client-acknowledge receiver.
             * Receive message and process it.
             * Acknowledge message.
             */
             try {
                System.out.println("  RECEIVER: Created client-acknowledge session");
                queueReceiver = queueSession.createReceiver(queue);
                queueConnection.start();
                message = (TextMessage) queueReceiver.receive();
                System.out.println("  RECEIVER: Processing message: " 
                    + message.getText());
                System.out.println("  RECEIVER: Now I'll acknowledge the message");
                message.acknowledge();
            } catch (JMSException e) {
                System.out.println("Exception occurred: " + e.toString());
                exitResult = 1;
            } finally {
                if (queueConnection != null) {
                    try {
                        queueConnection.close();
                    } catch (JMSException e) {
                        exitResult = 1;
                    }
                }
            }
        }  	    
    }
    
    /**
     * The AsynchSubscriber class creates a session in AUTO_ACKNOWLEDGE mode
     * and fetches several messages from a topic asynchronously, using a 
     * message listener, TextListener.
     * <p>
     * Each message is acknowledged after the onMessage method completes.
     *
     * @author Kim Haase
     * @version 1.6, 08/18/00
     */
    public class AsynchSubscriber extends Thread {

        /**
         * The TextListener class implements the MessageListener interface by 
         * defining an onMessage method for the AsynchSubscriber class.
         *
         * @author Kim Haase
         * @version 1.6, 08/18/00
         */
        private class TextListener implements MessageListener {
            final SampleUtilities.DoneLatch  monitor =
                new SampleUtilities.DoneLatch();

            /**
             * Casts the message to a TextMessage and displays its text.
             * A non-text message is interpreted as the end of the message 
             * stream, and the message listener sets its monitor state to all 
             * done processing messages.
             *
             * @param message	the incoming message
             */
            public void onMessage(Message message) {
                if (message instanceof TextMessage) {
                    TextMessage  msg = (TextMessage) message;
                    
                    try {
                        System.out.println("SUBSCRIBER: Processing message: " 
                                           + msg.getText());
                    } catch (JMSException e) {
                        System.out.println("Exception in onMessage(): " 
                                           + e.toString());
                    } 
                } else {
                    monitor.allDone();
                }
            }
        }

        /**
         * Runs the thread.
         */
        public void run() {
            TopicConnectionFactory  topicConnectionFactory = null;
            TopicConnection         topicConnection = null;
            TopicSession            topicSession = null;
            Topic                   topic = null;
            TopicSubscriber         topicSubscriber = null;
            TextListener            topicListener = null;

            try {
                topicConnectionFactory = 
                    SampleUtilities.getTopicConnectionFactory();
                topicConnection = 
                    topicConnectionFactory.createTopicConnection();
                topicConnection.setClientID("AckEquivExample");
                topicSession = topicConnection.createTopicSession(false, 
                    Session.AUTO_ACKNOWLEDGE);
                System.out.println("SUBSCRIBER: Created auto-acknowledge session");
                topic = SampleUtilities.getTopic(topicName, topicSession);
            } catch (Exception e) {
                System.out.println("Connection problem: " + e.toString());
                if (topicConnection != null) {
                    try {
                        topicConnection.close();
                    } catch (JMSException ee) {}
                }
    	        System.exit(1);
            }
            
            /*
             * Create auto-acknowledge subscriber.
             * Register message listener (TextListener).
             * Start message delivery.
             * Send synchronize message to publisher, then wait till all
             *   messages have arrived.
             * Listener displays the messages obtained.
             */
            try {
                topicSubscriber = topicSession.createDurableSubscriber(topic,
                     "AckEquivExampleSubscription");
                topicListener = new TextListener();
                topicSubscriber.setMessageListener(topicListener);
                topicConnection.start();

                // Let publisher know that subscriber is ready.
                try {
                    SampleUtilities.sendSynchronizeMessage("SUBSCRIBER: ", 
                                                            CONTROL_QUEUE);
                } catch (Exception e) {
                    System.out.println("Queue probably missing: " + e.toString());
                    if (topicConnection != null) {
                        try {
                            topicConnection.close();
                        } catch (JMSException ee) {}
                    }
    	            System.exit(1);
    	        }

                /*
                 * Asynchronously process messages.
                 * Block until publisher issues a control message indicating
                 * end of publish stream.
                 */
                topicListener.monitor.waitTillDone();
                topicSubscriber.close();
                topicSession.unsubscribe("AckEquivExampleSubscription");
            } catch (JMSException e) {
                System.out.println("Exception occurred: " + e.toString());
                exitResult = 1;
            } finally {
                if (topicConnection != null) {
                    try {
                        topicConnection.close();
                    } catch (JMSException e) {
                        exitResult = 1;
                    }
                }
            }
        }	    
    }

    /**
     * The MultiplePublisher class creates a session in AUTO_ACKNOWLEDGE mode
     * and publishes three messages to a topic. 
     *
     * @author Kim Haase
     * @version 1.6, 08/18/00
     */
    public class MultiplePublisher extends Thread {
        
        /**
         * Runs the thread.
         */
        public void run() {
            TopicConnectionFactory  topicConnectionFactory = null;
            TopicConnection         topicConnection = null;
            TopicSession            topicSession = null;
            Topic                   topic = null;
            TopicPublisher          topicPublisher = null;
            TextMessage             message = null;
            final int               NUMMSGS = 3;
            final String            MSG_TEXT = 
                              new String("Here is an auto-acknowledge message");

            try {
                topicConnectionFactory = 
                    SampleUtilities.getTopicConnectionFactory();
                topicConnection = 
                    topicConnectionFactory.createTopicConnection();
                topicSession = topicConnection.createTopicSession(false, 
                    Session.AUTO_ACKNOWLEDGE);
                System.out.println("PUBLISHER: Created auto-acknowledge session");
                topic = SampleUtilities.getTopic(topicName, topicSession);
            } catch (Exception e) {
                System.out.println("Connection problem: " + e.toString());
                if (topicConnection != null) {
                    try {
                        topicConnection.close();
                    } catch (JMSException ee) {}
                }
    	        System.exit(1);
            }

            /*
             * After synchronizing with subscriber, create publisher.
             * Send 3 messages, varying text slightly.
             * Send end-of-messages message.
             */
            try {
                /*
                 * Synchronize with subscriber.  Wait for message indicating 
                 * that subscriber is ready to receive messages.
                 */
                try {
                    SampleUtilities.receiveSynchronizeMessages("PUBLISHER: ", 
                                                              CONTROL_QUEUE, 1);
                } catch (Exception e) {
                    System.out.println("Queue probably missing: " + e.toString());
                    if (topicConnection != null) {
                        try {
                            topicConnection.close();
                        } catch (JMSException ee) {}
                    }
    	            System.exit(1);
    	        }

                topicPublisher = topicSession.createPublisher(topic);
                message = topicSession.createTextMessage();
                for (int i = 0; i < NUMMSGS; i++) {
                    message.setText(MSG_TEXT + " " + (i + 1));
                    System.out.println("PUBLISHER: Publishing message: " 
                        + message.getText());
                    topicPublisher.publish(message);
                }
                
                // Send a non-text control message indicating end of messages. 
                topicPublisher.publish(topicSession.createMessage());
            } catch (JMSException e) {
                System.out.println("Exception occurred: " + e.toString());
                exitResult = 1;
            } finally {
                if (topicConnection != null) {
                    try {
                        topicConnection.close();
                    } catch (JMSException e) {
                        exitResult = 1;
                    }
                }
            }
        }
    }
    
    /**
     * Instantiates the sender, receiver, subscriber, and publisher classes and 
     * starts their threads.
     * Calls the join method to wait for the threads to die.
     */
    public void run_threads() {
        SynchSender        synchSender = new SynchSender();
        SynchReceiver      synchReceiver = new SynchReceiver();
        AsynchSubscriber   asynchSubscriber = new AsynchSubscriber();
        MultiplePublisher  multiplePublisher = new MultiplePublisher();
        
        synchSender.start();
        synchReceiver.start();
        try {
            synchSender.join();
            synchReceiver.join();
        } catch (InterruptedException e) {}

        asynchSubscriber.start();
        multiplePublisher.start();
        try {
            asynchSubscriber.join();
            multiplePublisher.join();
        } catch (InterruptedException e) {}
    }

    /**
     * Reads the queue and topic names from the command line, then calls the
     * run_threads method to execute the program threads.
     *
     * @param args	the topic used by the example
     */
    public static void main(String[] args) {
        AckEquivExample  aee = new AckEquivExample();
        
        if (args.length != 2) {
    	    System.out.println("Usage: java AckEquivExample <queue_name> <topic_name>");
    	    System.exit(1);
    	}
        aee.queueName = new String(args[0]);
        aee.topicName = new String(args[1]);
        System.out.println("Queue name is " + aee.queueName);
        System.out.println("Topic name is " + aee.topicName);

    	aee.run_threads();
    	SampleUtilities.exit(aee.exitResult);
    }
}
